class DoubleKeyedHash
  attr_accessor :internal_hash
  def initialize
    @keys1 = {}
    @internal_hash = {}
  end

  def []=(key1,key2,value)
    @keys1[key2] = key1
    @internal_hash[key1] = value
  end

  def [] key
    @internal_hash[key] || @internal_hash[@keys1[key]]
  end

  def delete(key)
    t_key = @keys1[key]
    if t_key
      @keys1.delete(key)
      @internal_hash.delete(t_key)
    else
      @keys1.delete_if { |key,value| value == key }
      @internal_hash.delete(key)
    end
  end

  def each
    @internal_hash.each { |key,value| yield(key,value)}
  end
end